1. Field of the Invention
This invention relates to methods of and apparatus for photographic movie film to electronic video signal conversion, and to movie cameras particularly, but not exclusively, suitable for use in association with such conversion.
2. Description of the Prior Art
When a photographic movie film is converted to a video signal in a telecine, each frame of the film must be mechanically positioned so as to be aligned in the same position as the previous frames, to enable an accurately framed video signal to be derived. Hitherto, this has been done by pin registration, wherein an interference fit, slightly tapered pin is fitted into the film sprocket holes. Due to mechanical inaccuracies, this pin registration method does not give perfect results, and in consequence there may be an irritating lack of steadiness (so-called weave) in the image reproduced from the video signal. There are, moreover, other problems with this pin registration method. In particular, due to mechanical limitations, the conversion cannot be performed in real time, and typically the transport speed is as low as two frames per second. Also, there is a risk of damage to the sprocket holes by the tightly fitting pin. There is also the associated problem that movie cameras are noisy in operation due to the operation of the mechanism which meshes with the film sprocket holes to advance the film.